public class Controller { // numbers represent coordinate spot on grid pane [col][row] @FXML Button b00; @FXML Button b10; @FXML Button b20; @FXML Button b30; @FXML Button b40; @FXML Button b50; @FXML ...

I installed Scene Builder 11.0.0, made a new FXML file, inserted a TabPane as the root component, and inserted a GridPane into the first tab. I did all of them by dragging the components into the area ...